const fs=require('fs');
function myReadFile(filename){
	return new Promise((resolve,reject)=>{
		fs.readFile(filename,'utf-8',(err,data)=>{
			err?reject(err):resolve(data.length);
		}).catch((err)=>{console.log(err)});
});
async function abc(){
	let r1=await myReadFile('./files/a.txt');
	/*.catch(err=>{
		console.log(err);
	});*/
	let r2=await myReadFile('./files/b.txt');
	/*.catch(err=>{
		console.log(err);
	});*/
	let r3=await myReadFile('./files/c.txt');
	/*.catch(err=>{
		console.log(err);
	});*/
	console.log(r1);
	console.log(r2);
	console.log(r3);
}
abc();